1. Field of the Invention
This invention relates generally to tamper evident end closures for containers, and more particularly, to an end closure for a container for retaining a comestible product.
2. Description of the Prior Art
Containers of the type with which the present invention is concerned include end closures which maintain the container in a sealed condition after packaging and provide a non-resealable top or other means to indicate tampering with the container if the end closure is moved.
One type of previously available tamper evident container closure includes a rotatable cap portion formed with a knife or other means to engage a weakened annular panel portion in the end of the container. As the cap portion is rotated, the knife or other projections engage the weakened portion of the container end, causing the weakened panel to open. The weakened panel may be detached from the end of the container or may be partially inserted therein. A disadvantage of this type of container is that the aperture opened in this fashion is relatively small compared to the entire diameter of the container. As such, these types of closures are undesirable for use with wide mouth containers. These types of containers are disclosed in U.S. Pat. Nos. 3,877,604 and 3,726,432.
Another type of conventional means for indicating tampering involves the use of specially designed caps for bottles or containers having an external thread. As the overcap is rotated about the end of the container, a portion of the overcap brakes free, indicating tampering with the container. Although these devices provide a good indication of tampering, they are most useful with containers such as glass jars or bottles, wherein the seal of the end of the container is supplied by an external element which is not integrally formed with the container. This second type of closure is disclosed in U.S. Pat. Nos. 2,054,033 and 2,560,793.
It is also known to provide a sealed container with a member located at the sealed end thereof which is provided with a cutting edge. The member severs the tips of a plurality of projections in the container end in order to create a plurality of dispensing openings. This type of container opening device which is disclosed in U.S. Pat. No. 3,355,069, is not compatible with the opening of a wide mouth container.
U.S. Pat. No. 4,567,995 in the name of the same inventor as the inventor herein discloses an end closure for a container having a closed end with a cover rotatable thereabout. The closed end has a raised portion which is engaged by a knife blade integral with the cover. As the cover is rotated, the blade severs the raised portion, revealing an aperture providing access into the container. In this device, the closed end is not completely opened.
U.S. Pat. No. 4,598,837, also issued to the same inventor as the inventor herein, discloses a tamper evident element in a container wherein the rotation of an outer rotatable element causes an integral knife blade to sever and detach said element from the container, thus evidencing tampering when the cover is moved. This type of container is suitable for retaining food products in which small amounts are used at a time, but as is the case with the prior art referred to above, is not suitable for retaining food products such as frozen juices which, when the container is opened, are intended to be totally discharged from the container promptly or after a short storage period only.
Thus, it is desired to provide a tamper evident closure for wide mouth containers which can be used for packaging comestibles intended to be discharged in bulk from the container. It also is desired to provide a tamper evident container in which the rotating overcap knife blade which opens the container by rotation of the overcap is provided with structure to automatically engage a weakened raised rib of the container and maintain alignment of the blade with the rib.
The closure of the present invention includes an overcap rotatably secured to the closed end of a container and is provided with an integral knife blade. Twisting the overcap relative to the container causes the knife to engage and sever the raised rib of the container to totally remove a significant portion of the end of the container. The invention is also provided with a raised hollow lug in the end portion of the container which, while the container is sealed, projects through a corresponding aperture in the overcap. The overcap aperture is provided with a knife edge which, when the overcap is rotated, severs the raised lug, evidencing tampering.